The present invention relates to a storage apparatus and a storage area arrangement method, and, for example, can be suitably applied to a storage apparatus that provides a storage area, which is capable of dynamically enhancing its capacity, to a host system.
Conventionally, in a storage system storing data using a storage apparatus, there is a method of managing a plurality of hard disks according to the RAID (Redundant Array of Independent/Inexpensive Disks) system. In addition, at least one or more logical volumes (hereinafter referred to as the “logical volumes”) are formed on a physical storage area provided by the plurality of hard disks.
Further, in recent years, proposed is storage area dynamic allocation technology of providing a virtual volume (this is hereinafter referred to as the “virtual volume”) to a host system based on a plurality of logical volumes and dynamically allocating the storage area of a logical volume to the virtual volume according to a request from the host system without creating fixed-capacity logical volumes from the storage area of the hard disks (for instance, refer to Japanese Patent Application No. 2003-015915; “Patent Document 1”). According to this storage area dynamic allocation technology, it is possible to dynamically enhance the virtual volume.
Nevertheless, when operating this storage area dynamic allocation technology on a long-term basis, there are cases where the allocated storage area in the logical volume being used by the virtual volume becomes biased. Consequently, access will be concentrated on a specific logical volume, and there is a risk that the overall response performance to requests from the host system will deteriorate.